Genetics and Criminal Behaviour: Biomechanisms in Sentencing (A Student’s Perspective)
Sentencing is an important component of the judicial system, the rules of which are detailed in Part XXIII of the Criminal Code. Objectives of sentencing are highlighted in section 718 of the Criminal Code which include crime prevention, maintenance of respect for the law, maintenance of safety for society, deterrence of unlawful conduct, and rehabilitating offenders. In crafting a sentence, a judge must consider both the offence and the degree of responsibility of the offender, and the sentence must be proportionate to these two factors. Uniformity in sentencing is important and thus a similar sentence should be delivered to "similar offenders for similar offences committed in similar circumstances". This blawg briefly investigates how Canadian courts consider individual circumstances, with a comment on genetics, in the design of a sentence.
When reasonable, a judge should consider sanctions other than imprisonment for an offender and pay special attention to the circumstances of Indigenous offenders when deciding a sentence. Case law has clarified that rehabilitation and reintegration of Indigenous offenders should be the focus of sentencing provisions in the absence of aggravating factors. However, when considering “an accused's aboriginal background, the principles of restorative justice should not outweigh the principles of denunciation and deterrence in all cases." Overall, the fact that an offender is Indigenous may be mitigating in nature due to the “unique systemic or background factors” of Indigenous peoples.
Canadian courts also treat young offenders differently based on the Youth Criminal Justice Act in order to account for the reduced level of maturity of young people. Mental illness may also be an important consideration in a judgement for offenders of any age. Under section 16 (1) of the Criminal Code, people with mental illness who commit a criminal offence are not criminally culpable if the “mental disorder ... render[s] the person incapable of appreciating the nature and quality of the act or omission or of knowing that it was wrong.” In general, a mental disorder will be viewed by the courts as a mitigating factor and sentencing will shift towards rehabilitation. However, if the accused is not cooperative in the rehabilitation process or the danger posed by the accused outweighs the goal of rehabilitation, then regular sentencing provisions apply. For example, in R v Barnes, the accused was not diagnosed with a mental illness but psychological and psychiatric difficulties were considered as mitigating factors in his sentence.
The court will consider mental health and social circumstances when sentencing a convict. Should the court consider genetic predispositions of criminal behaviour (not a mental disorder) in the process of sentencing?
In 1984, researchers compared court convictions of 14,427 adoptees who were adopted between 1927-47 in a northern European nation with those of their adopted and biological parents. The researchers found a correlation between adoptees and their biological parents for property crimes and a lack of such correlation with the adoptees and their adopted parents. This early study suggested the possibility that heritable factors may impose a risk of criminal behavior. More recent studies have attempted to correlate the expression of certain genes with behaviour. Much attention has been payed to a gene called monoamine oxidase A (MAOA), which encodes a protein within the brain responsible for the degradation of several neurotransmitters, and ultimately plays an important role in brain function. A 2002 study revealed that male children who were maltreated were more likely to develop antisocial behavior if they had a variant of the MAOA gene that conferred low activity compared to children with the MAOA gene conferring high activity. A 2015 study of Finnish prisoners discovered that same low activity MAOA gene associated with severely violent crimes. These data indicate that heritable factors can indeed confer a greater risk of violence, and thus criminal behaviour.
To investigate the effect of a biological inclination, or biomechanism, towards criminality, Aspinwall and colleagues designed a study that looked at the effects of expert testimony of a biomechanism on the length of sentencing from 181 (164 participating) US state trial judges. The judges were given a hypothetical case (based on Mobley v State), where the accused, a diagnosed psychopath, brutally battered the victim, showing no remorse. All the judges heard expert testimony describing the psychopathy of the accused but two groups of judges (half) were given additional expert testimony explaining the biomechanism of the accused psychopathy, which was associated to low activity MAOA and other neurological factors (biomechanism present group). Then, within each of the biomechanism present and absent groups, either the prosecution argued that the psychopathy of the accused would likely lead to future violent crime or the defence argued that the psychopathy of the accused should be viewed as a mitigating factor because the accused has a harder time controlling his impulses. The key points of the study revealed that the presence of a biomechanism explanation from expert testimony resulted in an average sentencing of 12.83 years compared to 13.93 years without a biomechanism, regardless of the biomechanism being argued by the prosecution or defence. However, presentation of the biomechanism by the defence resulted in more judges citing the biomechanism as a mitigating factor.
Assuming Canadian judges would be influenced by the explanation of criminal behaviour through a biomechanism in a similar manner as US judges, the Aspinwall study suggests that biomechanisms may act as mitigating factors. Indeed, in the United States, research on the development of adolescent brains influenced the US Supreme Court to develop law which mitigates the criminal culpability of adolescents. Research studying the effect of other biomechanisms on sentencing will likely lead to additional invaluable information.
As more and more human genomes are being sequenced, criminal psychology will undoubtedly be complicated with more criminal associated gene variants. The fundamental question is if a certain gene or group of genes imposes an increased risk of violence, impulsiveness and thus criminality, then should the accused be judged with the same mens rea standards as everyone else? If not, which would be true for crimes that involve subjective tests, then the biological predisposition to criminality may serve as a mitigating factor. Importantly, litigators should be conscious that evidence of a biomechanism causing the predisposition to criminality may be important for reductions in sentencing or alternatives to prison.
 Criminal Code, RSC 1985 c C-46, s 718.
 Criminal Code, RSC 1985 c C-46, s 718.1.
 Criminal Code, RSC 1985 c C-46, s 718.2 (b).
 Criminal Code, RSC 1985 c C-46, s 718.2 (e).
 R v Kakekagamick,  SCCA No 34, 2007 CarswellOnt 3063; R v Ipeelee, 2012 SCC 13, 2012 CarswellOnt 4375 [Ipeelee].
 CED 4th (online), Sentencing, “Framework of Sentencing” (I.1.(a)).
 Ipeelee, supra note 5 at para 73.
 Youth Criminal Justice Act, SC 2002, c 1.
 Criminal Code, RSC 1985 c C-46, s 16 (1); Li, Re, 2009 CarswellMan 439; R v Race, 2014 NSSC 6, 2014 CarswellNS 42; R v McBride, 2013 ONCJ 390, 2013 CarswellOnt 9813.
 CED 4th (online), Sentencing, “Factors Considered in Passing Sentence” (II.1.(c)).
 R v Badria, 2017 ONSC 5389, 2017 CarswellOnt 14106; R v Foote, 44 Nfld & PEIR 271, 1983 CarswellNfld 77.
 R v Barnes,  AJ No 965, 2006 CarswellAlta 2032.
 Sarnoff A Mednick, William F Gabrielli & Barry Hutchings, "Genetic influences in crime convictions: evidence from and adoption cohort” (1984) 224 Science 891.
 Avshalom Capsi et al, “Role of genotype in the cycle of violence in maltreated children” (2002) 297 Science 851.
 J Tiihonen et al, “Genetic background of extreme violent behavior” (2015) 20 Mol Psychiatry 786.
 Lisa G Aspinwall, Teneille R Brown & James Tabery, "The double-edged sword: does biomechanism increase or decrease judges' sentencing of psychopaths?” (2012) 337 Science 846.
 Mobley v State, 455 SE 2d 61 (Ga, 1995).
 Laurence Steinberg, “The influence of neuroscience on US Supreme Court decisions about adolescents' criminal culpability” (2013) 14 Nature Rev Neurosci 513.